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GMC Sierra (14-18) LED Third Brake Light

4 Reviews

Brand: Morimoto




PART #: 1 x X3B45

*Guaranteed Fitment
Easy Return


Introducing the Morimoto X3B LED Third Brake Light Upgrade for 14-18 GMC Sierra trucks. This no-compromise upgrade combines style, performance, and utility to elevate your truck's aesthetics and safety. With its modern 3D red brake light optics, clear bed illumination, and sleek piano-black polycarbonate housing, the X3B is a striking departure from stock options. Functionally, the quad brake light optics, crafted from optical-grade red polycarbonate and powered by 3W LEDs, deliver high-intensity visibility day and night. An optional F1-style rapid flash module (SKU X3B01) adds extra flair. The X3B doesn't forget utility, featuring purpose-designed rail-style optics to effectively illuminate your truck bed without any dead spots. Installation is a breeze, as it seamlessly fits into the original mounting points and plugs into the stock wire harness, requiring no modifications. Plus, it complies with DOT and SAE regulations, backed by a five-year warranty. Elevate your GMC Sierra's style and safety with the Morimoto X3B LED Third Brake Light Upgrade.


  • Enhanced Visibility: 3D red brake light optics and powerful 3W LEDs for day and night visibility.
  • Stylish Design: Sleek piano-black polycarbonate housing with clear optics for a modern look.
  • Efficient Bed Lighting: Rail-style optics illuminate the truck bed evenly.
  • Easy Installation: Fits existing mounts, plugs into stock wire harness, no modifications needed.
  • Compliance and Warranty: Complies with regulations, backed by a 5-year warranty.


  • Third Brake Light: 1x Morimoto X3B LED Module (14-18 GMC Sierra)

  • Wiring: Plug and Play Adapter Harness

  • Optional Rapid Flash Module: Plug and Play Flasher (X3B01)


This Morimoto product includes a 5 Year limited warranty, serviced and supported by the Morimoto team in Atlanta, GA. This warranty does not cover modifications, alterations, or misuse. For additional information, Click Here.


  • Input: GM Multi-Pin OEM

  • Housing: Piano Black Polycarbonate

  • Lens: UV-Resistant Clear Polycarbonate

  • Bed Light: White (3W)



  • GMC Sierra 1500/HD: 2014-2018

  • Replaces GM Part #: 23509162, 20979071

  • NOTE: These housings have been designed for, and tested on, US-Spec vehicles. Other countries' compatibility may vary and is not guaranteed nor always known.


DOT, SAE Compliant


Just Right: Yes, we know. We know. You have been looking for a third brake light upgrade for a while now, only to retreat every time. Discouraged when the search returns no more than the same old variety of el-cheapo options out there. The X3B from Morimoto is different though. It's the one you've been waiting for. It's a no-compromise brake and bed light that offers the perfect pairing of style, performance, and utility, and its now available for your 14-18 GMC Sierra truck.

Style: Modern headlights have come a long way. Modern tail lights have come a long way... yet GMC is still specifying the same basic 20-year-old third brake lights on even their most modern trucks. Why? The X3B is the perfect grand finale for detail-oriented enthusiasts who just say no to stock. The pronounced 3D red brake light optics are as modern as it gets, yet tasteful. Complimented by the clear optics that illuminate the bed, and all wrapped up inside a piano-black polycarbonate housing. Here, form meets function.

Brake Lights: Here, function meets form, because the quad brake light optics are just as effective as they are attractive. Four jewel-like optics molded from optical-grade red polycarbonate paired with powerful 3W LEDs create a high-intensity brake light setup that's easily visible both day and night. An F1-style rapid flash module is also available, and easy to install (SKU X3B01).

Bed Lights: Are usually an afterthought, but not with the Morimoto X3B LED brake light modules. Optically engineered rail-style optics have been purposefully designed to effectively illuminate your bed without dead spots. While the X3B looks cool, its also a major upgrade for enthusiasts who value utility, and actually use their trucks too.

Easy Install: The X3B re-uses all of the original mounting points, fits like the factory brake light, and will plug into the stock wire harness. There are no modifications required for the installation.

Style and Safety: All Morimoto assemblies are designed to comply with all DOT, SAE regulations for rear-facing lamps. We pride ourselves on offering stylish, high-performance and safe products for serious enthusiasts, which is why all new Morimoto products are verified by trusted third party labs for compliance and are backed with an industry-leading five year warranty.

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